The invention relates to an arrangement for conveying sheet quires, in particular supplied to at least one gathering area. Such an arrangement comprises at least two successively arranged conveying devices, wherein the front conveying device, in the conveying direction, has a lower speed than the one in the rear. The arrangement also includes at least one ionization device for the electrostatic charging of the sheet quires. The invention furthermore relates a method for joining the sheet quires.
Conveying arrangements of the above type are used to supply a continuous flow of sheets or sheet quires that may arrive from a cross cutter to a gathering area. Conveying arrangements of this type operate at a relatively high speed. Given such high speeds, it is difficult to deposit the sheet quires in a gathering area without damaging them. The speed of the sheets or sheet quires must be reduced drastically for the depositing, since an orderly deposit of the sheet quires is otherwise not possible. Until now, several production stages were successively connected to reduce the speed in case of high speed differences, which involved considerable structural expenditure.
A conveying arrangement or a conveying device of this type is disclosed in German Patent No. 2 100 980, in which the sheets and at least one of the conveying belts can be charged electrostatically with an ionization device to permit an electrostatic braking of the sheets. Ionization devices are preferably arranged for this purpose on both sides of the cut sheets that are conveyed along, thus permitting a controlled movement of the sheets to one of the gathering areas.
An arrangement for conveying, overlapping and depositing sheets of paper or the like, for example ejected from cross cutters, with the aid of a conveying belt and an additional, slower-moving conveying belt that is connected downstream in the conveying direction in a lower position, is disclosed in published German Patent Application No. 1 245 702. For this arrangement, the individual sheets are held in place on the slow moving belt, the so-called deceleration belt, by means of suction air. However, an arrangement of this type cannot be used if several sheets are stacked one above the other, in so-called sheet quires or paper quires.
German Patent No. 34 09 548, owned by the Assignee of the present application, discloses an arrangement and a method for decelerating and overlapping paper sheets in paper-processing machines. With this arrangement, the individual sheets or sheet quires are slowed down with the aid of at least one braking roller. A machine or method of this type and an arrangement of this type, however, is less suitable for use with sensitive paper sheets and very high speeds, since it can result in damage to the sheets or sheet quires.